Proteins play a role in neurological health and disorders. About 25% of proteins contain metals and these proteins are known as metalloproteins. Both blood plasma proteins and metalloproteins play an active role in stroke. These proteins may be quantified with approaches as simple as multiplexed assay to that of quantitative protein mass spectrometry (proteomics). Identification of present bound metals is more elusive. Inductively coupled plasma mass spectrometry (ICP-MS) is capable of both quantitation as well as speciation of metalloproteins when coupled with chromatography. Determination of metalloproteins, for use as a stroke determination tool, was performed by bottom up proteomics. Multivariate analysis was used to simplify the determination of important stroke biomarkers that were identified or quantified by quantitative multiplexed assays and tandem mass spectrometry, respectively.

While ICP-MS was used as a means for determination of metal containing species, atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is used for quantitation of volatile species. Typical means of APCI-MS are coupled with chromatography for separations prior to quantitation or directly performed by flow injection. Alternatively, gas chromatography mass spectrometry (GC-MS) also is capable of separating volatile molecules at low levels by using solid phase microextraction (SPME) fibers. In order to improve APCI-MS, it was proposed to modify an APCI source to incorporate a conductive SPME source that was capable of low solvent analysis for detection of volatile species. While commercial SPME fibers are produced from a variety of polymers, this modified APCI source was produced from multiwalled carbon nanotubes (MWCNT's) to ensure flexibility, improved surface area, and conductivity.